Signal generator



Nov. 18, 1941. H. R. wARNKE SIGNAL GENERATOR Filed Aug. 8, 1940 2Sheets-Sheet l Nov. 18, 1941. H. R. wARNKE SIGNAL GENERATOR Filed Aug.8, 1940 2 Sheets-Sheet 2 //IIIIIIIIII lll/1 IA Y.

Patented Nov. 18, 1941 2,263,313 i sional. asNEaaToa Herbert B. Warnke,East Orange, N. J., assignor to United States Instrument Corporation,East Orange. N. J., a corporation of New Jersey Application August 8,1940, Serial No. 351.787

12 Claims.

The present invention relates to alternating current generators andparticularly to manually operated generators of the permanent magnettype, adapted for the production i# an alternating current of a suitablefrequency for direct conversion into sound energy in the audible range.Such generators, which may be generally classified as signal generators,are commonly used in communication and signalling systems operablewithout batteries or other external sources of energy. In such uses, thegenerator of the present invention may be combined with a telephonereceiving and transmitting instrument, or may be used separately togenerate a signal current for giving a signal through the medium oi aloud speaker or other instrument for converting electrical energy intosound energy. This application is a continuation-impart of my copendingapplication Serial No. 290,922, illed August 18, 1939 which describesand claims the subject matter of Figures 1-4A inclusive of the presentapplication.

It is the general object of the present invention to provide a signalgenerator of novel. compact and inexpensive design. having considerablymore power than previous generators of the general type in question andof comparable size.

Previous generators of the same general type have employed toothedrotors which are revolved in close proximity to one end of a stationaryarmature and, to a certain extent, such devices produce the same resultas that sought by the present invention. but by reason of the novelconstruction of the generator to be hereinafter described, in which bothends of the armature are employed for alternately opening and closinggaps in the magnetic circuit, the nux density in the armature and therate of change are greatly increased. with a corresponding increase inthe signal current generated.

Another signal generator heretofore known employs a xed armature and atoothed rotor disposed adjacent each end of the armature. In this case,the generated signal current is stronger than in the case of a singletoothed rotor at one end of the armature, but the device employing twotoothed rotors is bulky and expensive.

In some of the combined telephone and signal generator devicesheretofore known, the telephone instrument and the generator have beenconstantly connected. with the result that when the generator isoperated, the audible signal is reproduced -in the adjacent instrument,where it serves no purpose, and the value of the signalling currentfurnished to the instrument at the other end of the line iscorrespondingly diminished.

With the foregoing considerations in view, it is an object o f theinvention to provide a generator of the type in question comprising anarmature assembly consisting of an armature disposed between twopole-pieces, a coil surrounding the armature, and a magnet forpolarizing the pole-pieces, and a ileld member surrounding the rotor andprovided with a plurality of magnetic elements arranged in closeproximity to the ends of the armature, so that when the armatureassembly and field member are rotated relative to each other, analternating magnetic flux is established in the armature, generating analternating current in the coil.

A further object of the invention is the provision of a telephone unitcomprising a casing, a receiving and transmitting instrument supportedin the casing, a signal generator likewise supported withinA the casing,means whereby the receiving and transmitting instrument is normallyconnected to the telephone conductors leading to another station, andmanually operable means for disconnecting the receiving and transmittinginstrument and connecting the signal generator to the telephoneconductors for lrnishing a signalling current to said conduc- A furtherobject is the provision of a signal generator of the nature describedabove,`embody ing automatic switching means operatively connected withthe handle of the generator, for connecting the generator into atelephone circuit when the handle is turned. at the same timedisconnecting the local telephone instrument from said circuit, saidautomatic switching means being adapted to disconnect the generator andreconnect the telephone instrument when the handle of the generator isreleased.

A further object is the provision, in a signal generator of the typedescribed, of a novel field member comprising a ring of non-magneticmaterial having a circular series of magnetic inserts therein, thepurpose of which is to avoid loss of power due to flux leakage.

Other and further objects, features and advantages of the presentinvention will be apparent to one skilled in the art from the followingdescription taken in connection with the accompanying drawings in which:

Figure l is a longitudinal section through a telephone unit including ama! generator Iccording to the present invention;

2 assasvs Figure 2 is a transverse section on line 2-2 of Figure 1; f

Figure3isasectionon1inel-2ofFigure1;

Figure 4 is a fragmentary detail view showing a modification of thestator element;

Figure 4A is a horizontal section on line A A of Figure 3;

Figure 5 is a longitudinal section through a modified form of signalgenerator, in which the Aarmature assembly is stationary and the iield lmember is rotated;

,Figure 6 is a transverse section on line I-l of Figure I Figure 7 is atransverse section on line 'I-'I Figure 8 is an enlarged fragmentaryhorizontal section on line l-l of Figure 5;

Figure 9 is an enlarged fragmentary section on line 0-0 of Figure 7; and

Figure 10 is a transverse section on line It-II 20 of Figure 5.

In order to facilitate an understanding of the invention, referenceismade to the embodiments thereof shown in the accompanying drawings anddetailed descriptive language is employed. g5

It will nevertheless be understood that no limitation of the inventionis thereby intended and that various changes and alterations arecontemplated such as would ordinarily occur to one skilled in the art to'which -the invention relates. Y 30 Referring' to Figure 1, thetelephone unit there illustrated comprises vgenerally a casing I0 inwhich is supported a telephone transmitting and receiving instrument'iland a signal generator indicated generally at I2. Thetelephone instru-lment is preferably of the batteryless type. a suitable instrument being`described and illustrated in the Turnbull and Warnke application filedDecember 4, 1937, Serial No. 178,150, now Patent No. 2,245,511, June.10, 1941. 'I'he details of the 40 transmitting and receiving instrument,however,v form no part of the present invention, and will not be furtherdescribed.

The signal generator comprises a stator and a rotor, the stator I3having a cylindrical outer 45 surface of a diameter to t closely withinthe casing Il. The preferred form of stator Il is illustrated in FigureZand comprises a ring of non-magnetic material, such as brass or thelike,

having a continuous series of spaced magnetic 50 inserts I4. a portionof each insert being exposed on the inner periphery of the stator.

The rotor, which is indicated generally by the reference character I5,comprises a permanent magnetl I5 of high coercive force disposed be- 85tween opposed pole-pieces I1 and Il. andan armature I9 clamped betweenthe pole tips of the pole-pieces Il and Il but magnetically insulatedtherefrom by means of brass spacers 2l. A coil l2| surrounds thearmature Il andis grounded I0 to one of the pole-pieces as at 22. Theentire assembly is held together by screws, the screws 2l extending frompole-piece to pole-piece, and engaging inV grooves 24 formed inthe upperand lower edgesof the magnet It. The screws 2l likewise extend frompole-piece to pole-piece, through suitable apertures formed in thearmature I5. and serve tomaintaln the coil 2I` in place on the armature.Obviously, the screws 2l and 25 mustbe of non-magnetic material; '1 0The pole-pieces are also spaced and insulated by means of non-magneticspacers 25 and 21 which aresecuredin placebetween likeendsof the opposedpole-pieces, by means of screws (see Fig- .l

ure 4A). A stub shaft 2l vis secured centrally of the non-magneticspacer 2l and is iournalled in the combination bearing and gear member2l, an

anti-friction-thrust bearing Il being preferably provided between theend of theshaft 2l and the member. The member 2! is in turn .lournalledin a bushing 34 mounted in the rear wall l5 of the casing Il. Similarly,a hollow shaft 3l secured centrally of the non-magnetic spacer 21 isjournalled is an anti-friction bearing 22 mounted 'in the transversepartition 33 of the casl gether as at 42. The gear 40 meshes with a gear4i formed on the member 29, while thegear 4I a meshes witha small gear44 formed on the shaft l 28. A crank 45 secured to the outer end of themember 29, and provided with a pivoted handle portion 46 provides meansfor revolving the ro- 'tor I2 through the medium of the gears 4I, 4I,4If

and 44. 4

The pin 3l, to which the lead 88 of the coil 2I is connected, 'makesconstant contact Vwith a spring contact member 4l which in turn is'electrically connected to a spring contact member Il. Two additionalspring contact members 4l and 5l are adapted to be normally engaged,thereby electrically connecting the lead il of the transmitting andreceiving instrument to the incoming conductor 52. The other incomingconductor 5l and the other lead 54 of the trans-k mitting and receivinginstrumentare grounded v to the casing as at 5l. v

The plunger 55, having lan enlarged head Il, is slidably mounted in asuitablel aperture through thewall of the casing III, and extends intoengagement with the spring contact member Il.

outward displacement of the plunger being pre-fk vented by means of anut 5l. Since the coil 2| is grounded to the rotor at 22, and thelatterk makes good electrical connection with the casing through thespacers 26 and 21, the bearings, and

the gear train, it will be apparent that whenthe plunger is in theposition illustrated in Figure.

l, the transmitting and receiving instrument is electrically connectedto the incoming conduc-V tors 52 and 53, but ify the plunger I5 iselevated so as to disengage the spring contact members v40 and 50, andengage the latter with the contact member 48, the transmitting andreceiving instrument will then bedisconnected and the coil 2I will beconnected to the incoming conductors The alternating ux which causes thegenera-4l tion of the signalling current is established in` the armatureIl vin the following manner. Re-

ferring to Figure 2. the elements I4 are sok spaced about the stator I3that at the time when'any' element I4, such as the element I4' in Figure2,

' is in a position toy complete ,the vshortestmagnetic path between thepole-piece Iliand the upper end of the armature Il, another element,auch as the element I4". is in position to forniv a part;

ofthe shortest magnetic path between the .polepiece Il` and the oppositeor lower end of the` armature Il. That being so, the `shortest 'mag-1netic path (i. e. the Path having the smallest air gaps) between thepole-piece II andthe "polepiece il will be established through themagnetic element Il', downwardly through the armature I9, through themagneticelement Il" and into the adjacent pole tip of the pole-piece I8.This will remain true until the upper end of the armature passes thecenter of the element Il', at which time the lower end of the amaturealso passes the center of the element I4". When this happens theshortest magnetic path from the pole-piece I1 to the pole-piece Il willbe established from the lower tip of the pole-piece I1 through theelement Il", upwardly through the armature I9 to the magnetic elementI4' and thence to the upper tip of the pole-piece Il. Thus it will beseen that during each revolution ol the rotor the magnetic flux in thearmature I9 passes through a number of cycles equal to the number of themagnetic elements Il in the stator. From this it follows that thegenerated frequency depends upon the number of magnetic elements in thestator, the gear ratios employed. and the speed with which the handle 4Iis turned, and the device is accordingly adaptable to the production ofa wide range of frequencies. If a constant frequency is desired, a smallelectric motor may be employed for revolving the rotor.

In the operation of the signal generator as described, the handle 46 isgrasped and revolved. preferably at a speed of about four revolutionsper second. 'I'he two small gears 40 and 44 may, for example, havetwenty teeth each and the two larger gears 4I and 4I may have fifty-fourteeth.

In this case, if the handle is rotated at four revo- 4 lutions persecond, the rotor will revolve at approximately twenty-nine revolutionsper second. Preferably about forty magnetic elements I4 are provided inthe stator I3, and the frequency of the generated signal current willtherefore be about 1160 cycles per second, which is a suitable frequencyfor direct conversion into sound energy.

If desired, for reasons of convenience or otherwise, the form of statorillustrated in Figure 4 may be employed. The stator I3' of Figure 4consists of an internally toothed ring of magnetic material, and ispreferably laminated. When this form of stator is used, the entirestator being of magnetic material, there will be a certain amount offlux leakage between the opposing pole-pieces of the rotor, the fluxpassing from one pole-piece into the adjacent tooth of the stator andout through the next tooth of the stator to the opposing pole-piece.Obviously, the flux passing by this route is not available forgenerating a current in the coil surrounding the armature.

It will be obvious that it is only necessary to produce a relativerotation between the rotor I2 and stator I3, and in certain applicationsit may be desirable to maintain the armature assembly stationary androtate the member I3, or to rotate both members in opposite directions.

In the modification illustrated in Figures 5-10 the armature assembly isstationary, and means are provided for rotating the field or magneticmember which surrounds the armature assembly. In this form of thedevice, the generator comprises a casing 60 adapted to be closed by acover plate 6|, which may be secured in place by any suitable means,such as screws 62. The polepieces 63 and 64 are secured to the end wall6I of the casing, as best seen in Figure 8, the magnet 66 beinginterposed between the pole pieces as in the previous case. The magnet08 is preferably held in place by means of non-magnetic screws 81extending between the pole-pieces and lying in grooves formed in theupper and lower surfaces of the magnet. As best seen in Figures 6 and 8,the amature 6l is not clamped between the pole tips, as in the form ofgenerator illustrated in Figures l-4. but is rigidly secured to thearmature suspension Il which is in turn secured to the adjacent polepiece ll as by means of screws. The armature suspension 89 is slotted asat 10 to provide a relatively thin bridge portion 1I to which thearmature 8l is secured by means of the screw 12. By reason of thisarrangement, the armature, which is itself rigid, is permitted a slightamplitude of vibration, the purpose of which will be hereinafterexplained.

A series-connected pair of coils 13 surrounds the armature and has oneof its leads 13' grounded to the casing il as at 14, the other lead 1I"extending outwardly of the easing and connecting to the contact point15, which is insulated from the casing. by a. block 16 of insulatingmaterial. 'I'he inner` ends of the pole-pieces $3, 64 are connected by abridge member 11, which carries a small conical protuberance 1l whichserves as a thrust bearing for the rotating mechanism, which will now bedescribed.

The rotating or field structure comprises a shaft 19 on which is secureda disc Ill and a gear 0I. 'I'he shaft 19 is Journalled in the sleeve l2'of a gear |12, which in turn is journalled in the boss l) of the coverplate 6|. Preferably an anti-friction bushing 84 separates the gear 82and the boss 83. The gear l2 meshes with a small gear I5 which issecured on a stub shaft I8 journalled in the cover plate 8|. The shaftI6 also carries a gear 81 which meshes with the gear II secured on theshaft 19.

'I'he outer end of the sleeve l2' threaded to receive the threadedcrank-shaft 88. It will be readily understood that when the latter isrotated by external means, the disc l0 is driven at high speed throughthe gears l2. 8l, 81, and BI.

The crank-shaft 8B has a pin and slot connection with a crank sleeve I9,the slots which cooperate with the pin ll being inclined so as to causethe sleeve I9 to move inwardly (to the left in Figure 5) upon beingturned in a clockwise direction relative to the shaft ll. The sleeve 89is normally maintained in its outward position by the spring 92. A crankarm 93, secured to the outer end of the sleeve l! has journalled thereona handle member 04. It will be apparent that when the latter is graspedand the crank rotated in the clockwise direction, the sleeve 89 firstmoves inwardly relative to the shaft 88, after which the latter isrotated. driving the disc Il in the manner heretofore described.

The disc I0 is provided with a circular series of magnetic elementslil', which extend into close proximity to the respective lends of thearmature 6I, and as the disc 80 is rotated, a high-frequency alternatingcurrent is generated in the coil 1I in the manner described inconnection with the device of Figures 1-4. It is to be noted, however,that the present modification is somewhat more efficient than the deviceof Figures 1 4, for the reason that the armature il, being free tovibrate somewhat. will move so as to reducethe air gap between each endof the armature and the approaching element l0', this movement beingreversed so as to maintain the reduced air gap as the element passes therespective armature end. In this way, a greater magnetic ux is caused topass through the armature than would otherwise be the case, and acisinternally portion of a v 4 cordingly a higher potential is generated inthe coil 1I. Also, the magnetic elements ll' are so shaped as to overliethe entire end surface of thearmatureandasmallpartoftheadjacent edge.thus decreasing the reluctance of the magnetic circuit.

1t should also be noted that the present type of armature suspension,the aforesaid advantage, maybe employed in lieu ofthat illustrated inFigures 14, in the devicein which the amature is rotated and the fieldmember is.

stationary.

In order that the signal generator Just described may be automaticallyconnected into the telephone circuit, and the local telephone instrumentdisconnected. switching means are provided as illustrated in Flgureb inwhich the reference character l5 designates the local'telephoneinstrument and the numerals It, l1 designate the conductors extending tothe station to be vthe spring contact member Il. The remaining springcontact member lll is connected to the conductor l1 which leads to theremote station. The conductor I8 which also leads to the remote station,connects with the conductor Il extending from the instrument Il to thecasing of the signal generator. When the spring contact member Ill is inthe position illustrated in Figure 5,

the instrument Il is Aconnected in the circuit leading tothe remotestation, and the signal generator is disconnected from said circuit.However, when the spring contact member lll is moved to the right, so asto engage contact member iii, they instrument Il is disconnected fromthe circuit and the signal generator'is connected into the o1rou1t. Thisresult is brought mooutl automatically by means of the slide ill. whichextends through-thel casing il and is provided with a head l forengagement with the free end of the spring contact member Ill. Theopposite end of the slide Iltis engaged by the forked end of a rocklever i, the latter being secured to the cover plate Il, by means of Iascrew I, in such a manner as to permit it to partake of the necessary,rocking movement. The bifurcated inner end of the rock lever |05embraces the crank-shaft Il, and is adapted to be engaged by the cranksleeve Il as the latter moves inwardly as previously described.

From the foregoing description it will be apparent that when the handleIl is grasped and vrotated in a clockwise direction, the sleeve Il movesinwardly, rocking the lever Il!y andcausing the slide IIJ .to move tothe right in Figure 5, thus springing the contact member i out ofengagement witn contact member n and into engagement with contact memberlli. When the handle is released, the spring I2 causes the sleeve l0 tomove outwardly, permitting the spring contact member Ill to re-engagecontact aseasvs the nange il of the easing 0l. The conductors l1. andil! extend'through suitable apertures in the pluto m.

Having thus described the invention, what is claimed as new and desiredvto be secured byyr Letters Patent is:

1. In an alternating current generator, an,

armature assembly comprisingfa vpair of opposed pole-pieces, anarmature, a permanent magnet between said pole-pieces for polarizing thesame, and al coil surrounding said armature;r a member encircling saidarmature assembly and f having a circular series of spaced magneticelements; and means for producingl relative rotal tion between saidamature assembly and said member, said armature assembly and memberbeing so constructed and arranged that uponV armature clamped betweenbut spaced and magnetically insulated from said pole-pieces, a permanentmagnet disposed between said pole-pieces for polarizing the same, and acoil surrounding said armature a rotor comprising a member having acircular series of spaced magnetic elements adapted to pass in closeproximity to the ends of said armature; and means for revolving saidrotor to cause an l alternating magnetic ilux to flow through saidarmature whereby an alterna current is generated in said coil. f

3. In an alternating current generator, a rotor comprising a pair ofopposed pole-pieces, an amature supported between` said pole-pieces andhaving its ends spaced between opposing poletips, a permanent magnetdisposed betweensaid pole-pieces for polarizing the same, and a coilsurrounding said armature;v a stator comprising a member having acircular series of spaced inagnetic elements disposed in close proximityto the orbit of theends of said amature, said magnetic elements being sospaced that when one of said elements forms a part ofA the shortestmagnetic circuit between one end of said armature and one of saidpole-pieces. another of said elements forms a part of the shortestmagnetic circuit between the opposite endof said armature and saidvother pole-piece, and vice versa; and means for revolving said rotor tocause an alternating magnetic flux to flow through said armature wherebyan alternating current is generated in said coil.

4. An alternating current generator according to claim 3, said statormember comprising an internally toothed ring of magnetic material,

5. An alternating current generator according to claim 3, said statormember comprising a ring of non-magnetic material having spaced insertsof magnetic'materlal. u

6. In an alternating. current generator. an armature assembly comprisinga pair of opposed pole-pieces, an armature supported between saidbetween said armature assembly and said memp ber, said armature lyand-member so constructed and arranged that upon said relative rotationsaid magnetic elements and the respective ends 'of said amature assemblypass each other in close proximity and in such space relation as tocause an alternating magnetic flux to ow in said armature whereby analternating current is generatedin said coil.

7. In an alternating current generator, an

armature assembly comprising a pair of opposed pole-pieces, asubstantially rigid armature supported between said pole-pieces andhaving its ends spaced between opposing pole-tips, said armature beingmounted for limited vibratory movement relative to said pole-pieces, apermanent magnet disposed between said pole-pieces for polarizing thesame, and a coil surrounding said armature; a member encircling saidarmature assembly and having a circular series of spaced magneticelements; and means for producing relative rotation between saidarmature assembly and said member, said armature assembly and memberbeing so constructed and arranged that upon said relative rotation said-magnetic elements and the respective ends oi said armature assemblypass each other in close proximity and in such space relation as tocause an alternating magnetic iux to ilow in said armature whereby analternating current is generated in said coil.

8. In an alternating current generator, a stator comprising a pair ofopposed pole-pieces, an armature supported between said pole-pieces andhaving its ends spaced between opposing poletips, a permanent magnetdisposed between said pole-pieces for polarizing the same, and a coilsurrounding said armature; a rotor comprising a member having a circularseries of spaced magnetic elements adapted to pass in close proximity tocause an alternating magnetic flux to flow through said amature wherebyan alternating current is generated in said coil.

9. In an alternating current generator, a rotor comprising a pair ofopposed pole-pieces, an armature supported between said pole-pieces andhaving its ends spaced between opposing poletips, a permanent magnetdisposed between said pole-pieces for polarizing the same, and a coilLsurrounding said armature; a stator comprising a member having acircular series of" spaced magnetic elements disposed in close proximityto the orbit of the ends of said armature, said magnetic elements beingso spaced that when one of said elements forms a part of the shortestmagnetic circuit between one end of said armature and one of saidpole-pieces, another of said elements forms a part of the shortestmagnetic circuit between the opposite end of said armature and saidother pole-piece, and vice versa; and means for revolving said rotor tocause an alternating magnetic flux to flow through said amature wherebyan alternating current is generated in said coil.

10. An alternating current generator according to claim 6, saidencircling member comprising an internally toothed ring 'of magneticmaterial.

11. An alternating current generator according to claim 6. saidencircling member comprising a ring of non-magnetic material havingspaced inserts ot magnetic material.

12. An alternating current generator according to claim 6, saidencircling member comprising a disc of non-magnetic material havingspaced axially projecting teeth of magnetic material.

HERBERT R. WARNKE.

